Multiple component mixing device

ABSTRACT

Apparatus for instantaneous ratioing and mixing of a multicomponent composition of at least three component ingredients wherein at least two of the ingredients are supplied in predetermined ratio and wherein total quantity of ingredients or the ratio of said two ingredients may be varied without influencing the relative amount of the third component.

United States Patent [191 Robbins 1 June 4, 1974 MULTIPLE COMPONENT MIXING DEVICE [75] Inventor: John E. Robbins, South Wigston,

England [73] Assignee: USM Corporation, Boston, Mass.

[22] Filed: Mar. 8, 1973 21 Appl. No.: 339,428

[30] Foreign Application Priority Data Mar. 21, 1972 Great Britain 13067/72 [52] US. Cl. 222/135, 222/275 [51] Int. Cl B67d 5/02 [58] Field of Search 222/132, 134, 135, 137.

[56] References Cited UNITED STATES PATENTS 3,071,293 1/1963 Lewis-Smith et a1. 222/135 3,304,966 2/1967 Reed 222/275 X 3,386,623 6/1968 Berrill et 211... 222/135 X 3,496,970 2/1970 Pontigny 222/135 X 3,664,551 5/1972 Ferrari 222/145 X Primary Examiner-Robert B. Reeves Assistant Examiner-Francis J. Bartuska Attorney, Agent, or FirmAubrey C. Brine; Vincent A. White; Richard B. Megley 1 5 7 1 ABSTRACT Apparatus for instantaneous ratioing and mixing of a multicomponent composition of at least three component ingredients wherein at least two of the ingredients are supplied in predetermined ratio and wherein total quantity of ingredients or the ratio of said two ingredients may be varied without influencing the relative amount of the third component.

7 Claims, 2 Drawing Figures smU 1m 2 PATENTEU N 4 \974 MULTIPLE COMPONENT MIXING DEVICE BACKGROUND OF THE INVENTION This invention is concerned with improvements in or relating to apparatus adapted for use in dispensing a composition provided by the mixing together a plurality of constituent compositions, and is an improvement in or modification of the invention described in US. Pat. No. 3,642,175 issued to the present inventors and also assigned to the assignee of the present invention.

In the above mentioned patent, there is described by way of example two dispensing apparatuses, each of which is adapted for use in dispensing a multiple component composition, and which are described in reference to their illustrative use in the mixing of polyhydroxyl and polyisocyanate compositions to form the reaction of the polyurethane composition dispensed.

In the utilization of such mixing and dispensing apparatus as above described, it has been found that means for providing a third constituent component to the mixing chamber, however not necessarily at the ratio determined by the previously described apparatus. Ac-

cordingly an independent third feeding device for the third of the constituent composition is necessary which is arranged so that its feed ratio may be made dependent upon such as the total of the first two components dispensed or with the ratio of one or the other first two components dispensed.

SUMMARY OF THE INVENTION This invention provides, in accordance with one of its several features, apparatus for use in dispensing a composition provided by the mixing together of three constituent compositions and comprising:

a. a mixing chamber to which the constituent compositions are fed, wherein the constituent compositions are mixed and from which mixed constituent composition is dispensed;

b, a first feeding device for feeding a first of said constituent compositions to the mixing chamber;

c. a second feeding device for feeding a second of said constituent compositions to the mixing chamber;

d. ratio control means adapted to vary the ratio in which the first and second constituent compositions are fed to the mixing chamber;

e. a third feeding device for feeding a third of said constituent compositions to the mixing chamber; and

f. control mechanism adapted to control the total quantity of mixed constituent composition dispensed from the mixing chamber, wherein the proportion of third constituent composition present in mixed constituent composition dispensed from the mixing chamber is independent of both the ratio control means and the control mechanism.

This invention provides, in accordance with another of its several features, apparatus for use in dispensing a composition provided by the mixing together of three or more constituent compositons and comprising:

a. a mixing chamber to which the constituent compositions are fed, wherein the constituent compositions are mixed and from which mixed constituent composition is dispensed;

b. a first feeding device for feeding a first of said constituent compositions to the mixing chamber;

c. a second feeding device for feeding a second of said constituent compositions to the mixing chamber;

d. ratio control means adapted to vary the ratio in which the first and second constituent compositions are fed to the mixing chamber; and

e. a third feeding device for feeding a third of said constituent compositions to the mixing chamber;

The construction and arrangement being such that in the use of the apparatus the third feeding device feeds a quantity of third constituent composition to the mixing chamber proportional to the total quantity of first and second constituent composition fed to the mixing chamber and independent of the ratio in which said first and second constituent compositions are so fed to the mixing chamber.

Apparatus as set out in the above paragraphs may operate in a holdup manner in which the first and second compositions are fed to the mixing chamber one after the other, to be mixed herein and then dispensed therefrom, the third feeding device feeding third constituent composition to the mixing chamber during the feeding thereto of either the first or the second constituent compositions: apparatus as set out in the last preceding paragraph may operate in a continuous" manner in which the three constituent compositions are fed to the mixing chamber at the same time to be dispensed directly from the mixing chamber, the first and second constituent compositions being fed to the mixing chamber at a desired rate ratio, the third constituent composition being fed to the mixing chamber at a rate proportional to the total rates of feeding of first and second constituent composition.

The above and other of the various objects and several features of this invention will become more clear from the following description, to be read with reference to the accompanying drawings, of the two illustrative apparatuses. It is to be understood that these illustrative apparatuses have been selected to illustrate this present invention by way of example only, and not by way of limitation thereof.

DESCRIPTION OF THE DRAWINGS In the accompanying drawings:

FIG. 1 is a schematic view of the first illustrative apparatus: and

FIG. 2 is a schematic view of the second illustrative apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to FIG. 1 of the drawings, the first illustrative apparatus is adapted for use in dispensing a multiple component, polyurethane composition and comprising a mixing chamber 10 of variable volume provided by a cylinder 12 and a piston 14, to which is secured a piston rod 16, fitting snugly therein. Connected to an end portion of the piston rod 16 remote from the piston 14 is a piston 18 slidably mounted in a cylinder 20. On admission of fluid under pressure to an inlet port 21 of the cylinder 20, the piston 14 may be moved within the cylinder 12 to decrease the volume ofthe mixing chamber 10, air flowing from the cylinder 20 through an exhaust port 22 thereof.

Extending into the cylinder 12 at lower portions thereof are first and second inlet ports 24, 26, respectively. Extending from the cylinder 12 at a lower portion thereof is an outlet port 28 controlled by an outlet valve (not shown). Mounted in the cylinder 12 is a stirrer 31 connected to a shaft 30 and means (not shown) for operating said shaft 30 and stirrer 31.

The first illustrative apparatus also comprises first and second storages comprising first and second tanks 48 and 68, respectively in which first and second constituent compositions, comprising, respectively, reactive hydroxyl groups and reactive isocyanate groups, are maintained under a pressure in excess of atmospheric pressure, and feeding means comprising first and second feeding devices 50,70 respectively adapted to feed first and second constituent composition respectively, from their respective tanks to the mixing chamber 10.

The first feeding device 50 comprises a cylinder 52 having a piston 54, to which is secured a piston rod 56, slidably mounted therein. Extending into an upper portion of the cylinder 52 is an inlet port 58, and extending from a lower portion of the cylinder is an exhaust port 60. A free, lower end portion of the piston rod 56 is bifurcated, a roller 62 extending between the bifurcated portions thereof.

The second feeding device 70 comprises a cylinder 72, of a diameter different from that of the cylinder 52, having a piston 74, to which is secured a piston rod 76, slidably mounted therein. Extendig into a lower portion of the cylinder 72 is an inlet port 78; extending from an upper portion of the cylinder is an exhust port 80. A free, upper end portion of the piston rod 76 is bifurcated, a roller 82 extending between the bifurcated portions thereof.

The feeding means also comprises operating mechanism 100 adapted to move the feeding means between first, second and rest conditions to feed constituent composition from the storages to the mixing chamber and comprising a correlating member 90 provided by an elongated bar, mounted on a pivot 92. The pivot is carried on a bracket 93 slidably mounted on a support arm 94.

The member 90 is provided with three slots 95, 96 and 97, extending lengthwise of the member and spaced at intervals from the pivot 92, respectively.

The operating mechanism 100 also comprises a fluid operated piston/cylinder operating device comprising cylinder 102 having a piston 104, to which is secured a piston rod 106, slidably mounted therein, ports 108, 110 extending into upper and lower portions of the cylinder respectively. A lower end portion of the rod 106 is bifurcated, a roller 112 extending between the bifurcated portions thereof.

The first illustrative apparatus also comprises control mechanism comprising a microswitch 120 secured to an upper end portion of the rod 106, a first contact 124 mounted at a fixed position on a support 122 and a second contact 126 mounted at an adjustably variable position on the support 122.

The piston rods 56, 76 and 106 are parallel, the rollers 62, 82 and 112 thereof extending through the slots 97, 95 and 96 of the correlating member, respectively. The piston rods 56 and 106 extend from the correlating member in the same direction, the piston rod 76 extending therefrom in the opposite direction.

A first supply conduit 64 extends from the first tank 48 through one-way valve 65 to the inlet port 58 of the cylinder 52; extending from the supply conduit 64, downstream of the valve 65 through a one-way valve 66 to the inlet port 24 of the cylinder 12 is a supply conduit 67.

A second supply conduit 84 extends from the second tank 68 through a one-way valve to the inlet port 78 of the cylinder 72; extending from the supply conduit 64, downstream of the valve 85 through a one-way valve 86 to the inlet port 26 of the cylinder 12 is a supply conduit 87.

The first illustrative apparatus however additionally comprises a third storage comprising a third tank 228 in which third constituent composition, specifically a colouring material, is maintained under a pressure in excess of atmospheric pressure, the feeding means comprising a third feeding device 230 adapted to feed third constituent composition from the tank 228 to the mixing chamber 10.

The third feeding device comprises a cylinder 232 having a piston 234, to which is secured a piston rod 236, slidably mounted therein. Extending into an upper portion of the cylinder are inlet and outlet ports 238 and 240, respectively, and extending into a lower portion of the cylinder is an exhaust port 241. An upper end portion of the piston rod 236 remote from the cylinder 232 is attached directly to the piston rod 106 of the operating mechanism 100, said piston rods 236 and 106 being co-linear.

A third supply conduit 244 extends from the third tank 228 through a one-way valve 245 to the inlet port 238 of the cylinder 232; a third delivery conduit 247 extends from the outlet port 240 through a one-way valve 246 to an inlet port 229 extending into the mixing chamber 10.

In the rest condition of the feeding means the correlating member is in a rest position, shown in dotted lines A in FIG. 1. In this condition, the mixing chamber contains a small amount of first constituent composition together with a small amount of third constituent composition, together with residual polyurethane composition from an immediately preceding cycle of operation of the apparatus.

On operation of a starter switch of the control mechanism to initiate an operating cycle of the apparatus fluid under pressure is admitted to the port of the cylinder 102, the port 108 thereof and the port 21 of the cylinder 20 being opened by the control mechanism to atmosphere.

The operating mechanism moves the correlating member clockwise (FIG. 1) about its pivot, forcing a first quantity of first constituent composition from the cylinder 52 through the port 58 along the conduits 64 and 67 through the one-way valve 66 and into the mixing chamber through the port 24, and a first quantity of third constituent composition from the cylinder 232 through the port 238 along the conduit 247 through the one-way valve 246 and into the mixing chamber through the port 229. A first proportionate quantity of second constituent composition is fed simultaneously into the cylinder 72 from the second storage, said quantity depending upon the position of the pivot 92 on the support arm 94.

On engagement of the microswitch with the contact 126, (with the feeding means in its first condition shown in FIG. 1, the correlating member 90 being in the position indicated B), the control mechanism reverses the direction of movement of the piston 104, fluid under pressure being admitted to the port 108, and the port 110 being opened to atmosphere.

The correlating member is now moved anticlockwise about the pivot 92, forcing the piston 74 downwardly to feed a first quantity of second constituent composition from the cylinder 72 along the conduits 84 and 87 through the one-way valve 86 and into the mixing chamber through the port 26. Simultaneously, a proportionate quantity of first constituent composition is fed into the cylinder 52 from the first storage, and third constituent composition is fed into the cylinder 232 from the third storage.

On the correlating member reaching the position in which it is indicated in dotted lines C in FIG. 1, in which the feeding means is in its second condition, the operating mechanism is maintained stationary whilst the constituent compositions are mixed within the mixing chamber and discharged by the piston 14 therefrom through the port 28.

The operating mechanism is then caused by the control mechanism to move the feeding means to its rest condition, in which the correlating member is in its rest position (indicated A), second, small quantity of first constituent composition and a second, small quantity of third constituent compoisition being fed to the mixing chamber, the first constituent composition acting to dissolve residual polyurethane composition, and simultaneously a second proportionate quantity of second constituent composition is fed into the cylinder 72. On reaching said rest condition, the microswitch 120 engages the contact 124 and the apparatus comes to rest.

The total quantity of first and second constituent composition fed to the mixing chamber may be varied by movement of the contact 126. Such movement of the contact 126 has no effect on the ratio in which the two constituent compositions are fed to the mixing chamber. The total quantity of first constituent composition dispensed from the mixing chamber in a particular operating cycle of the apparatus comprises the second quantity fed thereto in the immediately preceding cycle and the first quantity fed thereto in said particular cycle, and the quantity of second constituent composition fed to the mixing chamber in said particular cycle comprises the firstproportionate quantity fed from the storage thereof to the second feeding device in said particular cycle and the second porportionate quantity fed from the storage to the second feeding device in said immediately preceding cycle.

' The ratio of the transverse distance a from the connection of the piston rod 56 to the member 90 to the connection of the piston rod 106 to the member 90, to the transverse distance b, from the connection of the piston rod 76 to the member 90 to the connection of the piston rod 106 to the member 90, is equal to the inverse ratio of the cross-sectional areas of the cylinders 52 and 72. Specifically, in the first illustrative apparatus the ratio of said distance a/b is as shown in FIG. 1, 3/2, and the inverse ratio of the cross-sectional areas of the cylinder 52 (A) to that of the cylinder 72 (B) viz., B/A is also 3/2. Thus, the total quantity of first and second constituent composition fed to the mixing chamber in any one operation of the illustrative apparatus is independent of the distance of the pivot 92 from the piston rods. Thus, variation may be made to the ratio in which the first and second constituent compositions are fed to the mixing chamber (by movement of the bracket 93 on the support arm 94) without having any substantial effect to the total quantity of first and sec- 6 ond constituent composition fed to the mixing chamber.

Said total quantity of first and second constituent composition is thus dependent on the axial distance moved by the piston rod 106, as determined by the position of the contact 126. The total quantity at third constituent composition fed to the mixing chamber in an operating cycle of the first illustrative apparatus is also dependent upon the axial distance moved by the piston rod 106, and is of course not dependent upon the position of the pivot 92 and hence the ratio in which the first and second constituent compositions are mixed.

Thus, in the use of the first illustrative apparatus, variation may be made to both the total quantity of mixed constituent composition fed to the mixing chamber in an operating cycle thereof, and to the ratio in which the first and second constituent compositions are so fed, without causing variation to the proportion of third constituent composition present in mixed constituent composition dispensed from the mixing chamber.

The second illustrative apparatus is (FIG. 2) also adapted for use in dispensing a multiple component, polyurethane, composition, comprising a mixing chamber 124 comprising first and second inlet ports 126, 128 respectively and an outlet nozzle 129.

The second illustrative apparatus also comprises first and second storages comprising first and second tanks 132, 136 in which first and second constituent compositions, comprising, respectively, reactive hydroxyl groups and reactive isocyanate groups, are maintained and feeding means comprising first and second feeding devices 150, 170 adapted to feed first and second constituent composition, respectively, from their respective storages to the mixing chamber 124.

The first feeding device comprises a cylinder 152 having a piston 154, to which is secured a piston rod 156, slidably mounted therein. Extending into a lower portion of the cylinder 152 is an inlet port 158; extending into an upper portion of the cylinder is an exhaust port 160. A free, upper end portion of the piston rod 156 is bifurcated, a roller 162 extending between the bifurcated portions thereof.

The second feeding device comprises'a cylinder 172, of a diameter different from that of the cylinder 152, having a piston 174, to which is secured a piston rod 176, slidably mounted therein. Extending into a lower portion of the cylinder 172 is an inlet port 178; extending into an upper portion of the cylinder is an exhaust port 180. A free, upper end portion of the piston rod 176 is bifurcated, a roller 182 extending between the bifurcated portions thereof.

The second illustrative apparatus also comprises operating mechanism comprising a correlating member 190, provided by an elongated bar, mounted on a pivot 192. The pivot is carried on a bracket 193 slidably mounted on a support arm 194.

The member is provided with three slots 195, 196 and 197, extending lengthwise of the member and spaced at intervals from the pivot 192, respectively.

The operation mechanism also comprises a fluidoperated piston/cylinder operating device 200 comprising a cylinder 202 having a piston 204, to which is secured a piston rod 206, slidably mounted therein, ports 208, 210 extending into upper and lower portions of the cylinder 202 respectively. A lower end portion of the rod 206 is bifurcated, a roller 202 extending between the bifurcated portions thereof.

The operating mechanism also comprises a control device comprising a microswitch 220 secured to an upper end portion of the rod 206, a first contact 224 mounted at a fixed position on a support 222 and a second contact 226 mounted at a fixed position on the support 222.

The piston rods 156, 176 and 206 are parallel, the rollers 162, 182 and 212 thereof extending through the slots 197, 195 and 196 of the correlating member, respectively.

A first supply conduit 164 extends from the first tank 132 through a one-way valve 165 to the inlet port 158 of the cylinder 152; extending from the supply conduit 164, downstream of the valve 165 towards the mixing chamber 124 is a first delivery conduit 167.

The conduit 167 extends to a two-way valve 166. In a first condition of the valve 166, the conduit 167 is connected to the port 126 of the mixing chamber: in a second condition of the valve 166, the conduit is connected to a return conduit 169 leading back to the tank 132.

A second supply conduit 184 extends from the second tank 136 through a one-way valve 185 to the inlet port 178 of the cylinder 172; extending from the supply conduit 164, downstream of the valve 185 towards the mixing chamber 124 is a second delivery conduit 187.

The conduit 187 extends to a two-way valve 186. In the first condition of the valve 186, the conduit is connected to the port 128 of the mixing chamber: in a second condition of the valve 186, the conduit is connected to a return conduit 189 leading back to the tank 136.

The second illustrative apparatus however additionally comprises a third storage comprising a third tank 328 in which third constituent composition, specifically a colouring material, is maintained under a pressure in excess of atmospheric pressure, the feeding means comprising a third feeding device 300 adapted to feed third constituent composition from its storage to the mixing chamber 124.

The third feeding device comprises a cylinder 332 having a piston 334, to which is secured a piston rod 336, slidably mounted therein. Extending into a lower portion of the cylinder are inlet and outlet ports 338 and 340, respectively, and extending into an upper portion of the cylinder is an exhaust port 341. An upper end portion of the piston rod 336 remote from the cylinder 332 is attached directly to the piston rod 206 of the operating mechanism 200, said piston rods 336 and 206 being co-linear.

A third supply conduit 344 extends from the tank 328 through a one-way valve 345 to the inlet port 338 of the cylinder 332; extending from the outlet port 340 of the cylinder 332 towards the mixing chamber 124 is a third delivery conduit 347.

The conduit 347 extends to a two-way valve 346. In a first condition of the valve 346, the conduit 347 is connected to an inlet port 329 extending into the mixing chamber: in a second condition of the valve 346, the conduit is connected to a return conduit 349 leading back to the tank 328.

The valves 166, 186 and 346 are moved between their first and second conditions simultaneously by a solenoid control, (not shown), connected to the valves by a control arm, of the control mechanism of the illustrative apparatus.

On operation of a starter switch of the operating mechanism, fluid under pressure is admitted to the port 210 of the cylinder 202, the port 208 thereof being opened to atmosphere.

The operating device moves the correlating member clockwise about its pivot, first, second and third constituent compositions being drawn from their storages along the conduits 164, 184 and 344 through the oneway valves 165, 185 and 345 and into the cylinders 152, 172 and 332, respectively.

On engagement of the microswitch 220 with the contact 226, (with the apparatus in the condition shown on dotted lines in FIG. 2) the operating mechanism reverses the direction of movement of the piston 204, fluid under pressure being admitted to the port 208 and the port 210 being opened to atmosphere.

The'corelating member is now moved anticlockwise about the pivot 192, forcing the pistons 154, 174 and 334 downwardly to feed said first, second and third constituent compositions along the conduits 167, 187 and 347.

With the valves 166, 186 and 346 in their second conditions, the compositions are returned along the conduits 169, 189 and 349 to their storage tanks. On operation of an injector switch, the solenoid control operates to move the said valves to their first conditions, the constituent compositions then being delivered simultaneously to the mixing chamber wherein the compositions are mixed and from whichthe mixed constituent compositions are dispensed directly from the nozzle 129.

On completion of the flow from the nozzle of a desired quantity of mixed constituent compositions, the solenoid control is operated to return the valves 166, 186 and 346 to their second conditions.

On reaching the position in which it is shown in the drawing in which the feeding means is in its second condition, contact between the microswitch 220 and the contact 224 causes the operating mechanism to reverse the direction of movement of the correlating member.

The ratio of the transverse distance a, from the connection of the piston rod 156 to the member 190 to the connection of the piston rod 206 to the member 190, to the transverse distance b, from the connection of the piston rod 176 to the member 190 to the connection of the piston rod 206 to the member 190, is equal to the inverse ratio of the cross-sectional areas of the cylinders 152 and 172. Specifically, in the second illustrative apparatus the ratio of the distances a'/b' is shown in FIG. 3 to be 3/2, and the inverse ratio of the cross-sectional areas of the cylinder 152 (A') to that of the cylinder 172 (B) viz., B/A' is also 3/2. Thus, the total rate at which the first and second constituent compositions are delivered to the mixing chamber and dispensed therefrom in the operation of the illustrative apparatus is independent of the distance of the pivot 92 from the piston rods. Thus, variation may be made to the ratio in which the first and second constituent compositions are delivered to the mixing chamber (by movement of the brackt 193 on the support arm 194) without having any substantial effect on the total rate at which the first and second constituent compositions are delivered to the mixing chamber.

Having thus described my invention, what 1 claim as new and desire to secure by letters Patents of the United States is: g

1. Apparatus for use in dispensing a composition provided by the mixing together of at least three constituent compositions and comprising: first storage means for containing a first of said constituent compositions; second storage means for containing a second of said constituent compositions means for mixing constituent compositions; first and second cylindrical chambers of different diameters and having pistons slidable therein in one direction to feed one composition from the first storage means to the first chamber while the other composition is fed from the second chamber to the mixing device, said pistons being slidable in the opposite direction to reverse the actions of the chambers; correlating means comprising a pivoted member connected to the pistons and means connected to said member between the connections for said pistons for operating said member to operate the pistons alternately in said directions, the ratio of the distancesbetween the respective connections of the pistons of the first and second chambers and the connection for the operating means being equal to the inverse ratio of the diameters of the respective first and second chamber, the relation of said connections to the pivot of said member being so arranged as to cause the pistons to feed a predetermined ratio of said first and second compositions; third stage means for containing a third constituent composition, a third cylindrical chamber of predetermined diameter having a piston slidable therein in one direction to feed the third composition from the third storage means to the third chamber while one of the other compositions is fed from its chamber to the mixing device said third pistons being slidable in the opposite direction to reverse the action of its chamber, said third piston connected to said correlating intermediate said first and second pistons and co-linearly with said operating means, the realtion of said third piston connection to said correlating member being such that action of said third chamber and piston is independent of the spacing of the first and second chambers and piston and directly depending upon said operating means.

2. Apparatus according to claim 1 including means to adjust the distance between said pivot and the connection of the'operating means for varying the ratio of said first and second compositions fed by the pistons and maintaining constant the quantity of the third composition fed.

3. Apparatus according to claim 2 including means to vary the extent of movement as said correlating member varying the total quantity of compositions fed and maintaining constant the ratio of the first and second quantities fed.

4. Apparatus for use in dispensing a composition provided by the mixing together of at least three constituent compositions and comprising first feeding means operable to feed a first of said constituent compositions and comprising a cylindrical chamber having a piston slidably disposed therein; second feeding means operable to feed a second of said constituent compositions and comprising a cylindrical chamber having a piston slidably disposed therein; third feeding means operable to feed the third of constituent compositions and comprising a cylindrical chamber having a piston slidably disposed therein, said cylindrical chambers being of different diameters; correlating means controlling the operation of the first and second feeding means according to an operating ratio equal to the inverse ratio of the diameters of the first and second cylinders and controlling the operation of said third feeding means independent of the ratio of said first and second means, said correlating means being adjustable for varying the effectiveness of said operating ratio to vary the quantities of the first and second of the constituent compositions fed and maintaining constant the quantity of the third composition fed.

5. Apparatus as set forth in claim 4 wherein said correlating means comprises a pivoted member movable about a pivot and connected to the three pistons, and further including operating means for moving said pivoted member about its pivot and connected to said pivoted member between the said first and second piston connections to said pivoted member and co-linearly with said third piston, the ratio of the distances between the connections of the first and second pistons and the operating means being equal to the inverse ratio of the diameters of the first and second chambers.

ties fed by the first and second feeding means. 

1. Apparatus for use in dispensing a composition provided by the mixing together of at least three constituent compositions and comprising: first storage means for containing a first of said constituent compositions; second storage means for containing a second of said constituent compositions means for mixing constituent compositions; first and second cylindrical chambers of different diameters and having pistons slidable therein in one direction to feed one composition from the first storage means to the first chamber while The other composition is fed from the second chamber to the mixing device, said pistons being slidable in the opposite direction to reverse the actions of the chambers; correlating means comprising a pivoted member connected to the pistons and means connected to said member between the connections for said pistons for operating said member to operate the pistons alternately in said directions, the ratio of the distances between the respective connections of the pistons of the first and second chambers and the connection for the operating means being equal to the inverse ratio of the diameters of the respective first and second chamber, the relation of said connections to the pivot of said member being so arranged as to cause the pistons to feed a predetermined ratio of said first and second compositions; third stage means for containing a third constituent composition, a third cylindrical chamber of predetermined diameter having a piston slidable therein in one direction to feed the third composition from the third storage means to the third chamber while one of the other compositions is fed from its chamber to the mixing device said third pistons being slidable in the opposite direction to reverse the action of its chamber, said third piston connected to said correlating intermediate said first and second pistons and co-linearly with said operating means, the realtion of said third piston connection to said correlating member being such that action of said third chamber and piston is independent of the spacing of the first and second chambers and piston and directly depending upon said operating means.
 2. Apparatus according to claim 1 including means to adjust the distance between said pivot and the connection of the operating means for varying the ratio of said first and second compositions fed by the pistons and maintaining constant the quantity of the third composition fed.
 3. Apparatus according to claim 2 including means to vary the extent of movement as said correlating member varying the total quantity of compositions fed and maintaining constant the ratio of the first and second quantities fed.
 4. Apparatus for use in dispensing a composition provided by the mixing together of at least three constituent compositions and comprising first feeding means operable to feed a first of said constituent compositions and comprising a cylindrical chamber having a piston slidably disposed therein; second feeding means operable to feed a second of said constituent compositions and comprising a cylindrical chamber having a piston slidably disposed therein; third feeding means operable to feed the third of constituent compositions and comprising a cylindrical chamber having a piston slidably disposed therein, said cylindrical chambers being of different diameters; correlating means controlling the operation of the first and second feeding means according to an operating ratio equal to the inverse ratio of the diameters of the first and second cylinders and controlling the operation of said third feeding means independent of the ratio of said first and second means, said correlating means being adjustable for varying the effectiveness of said operating ratio to vary the quantities of the first and second of the constituent compositions fed and maintaining constant the quantity of the third composition fed.
 5. Apparatus as set forth in claim 4 wherein said correlating means comprises a pivoted member movable about a pivot and connected to the three pistons, and further including operating means for moving said pivoted member about its pivot and connected to said pivoted member between the said first and second piston connections to said pivoted member and co-linearly with said third piston, the ratio of the distances between the connections of the first and second pistons and the operating means being equal to the inverse ratio of the diameters of the first and second chambers.
 6. Apparatus according to claim 5 including means to adjust the distance between saId pivot and the connection of the operating means for varying the ratio of the respective quantities fed by the first and second feeding means and maintaining constant the quantity of the third composition fed.
 7. Apparatus according to claim 5 including means to vary the extent of movement of the pivoted member for varying the total quantity of the compositions fed and maintaining constant the ratio of the respective quantities fed by the first and second feeding means. 